The present invention is generally concerned with the transporting of fluent materials by means of collapsible rubberized tanks positioned within conventional van-type freight containers or trailer bodies. More specifically, the invention relates to a system for the handling and storage of the tanks. Collapsible rubberized storage tanks for liquids or other fluent materials have come into common usage as a convenient means for the transporting of such materials in transport containers more commonly associated with bulk materials, for example truck trailers, railroad cars, box containers, and the like. The patent to Headrick, U.S. Pat. No. 3,416,762, issued Dec. 17, 1968, is of interest in illustrating a rubberized tank or pillow tank of the type with which the present invention is generally concerned.
While the collapsible or flexible shipping container fills a definite need and provides significant advantages in enabling the use of conventional transport equipment, problems do arise in connection with its use, both because of the basic unloaded weight of the container, in some instances 750 pounds or more, and because of the substantial capacity thereof, normally between 2,000 and 3,000 gallons which, when dealing with a fluent silicate, as an example, could weigh more than 30,000 pounds.
A disadvantage inherently associated with the use of the tank within conventional transport vehicles is that, even when empty, the bulk of the tank generally precludes use of the vehicle for other transport usages. For example, subsequent to the delivery of a fluent product utilizing the tank, the collapsed tank remains on the floor of the trailer and the trailer returns empty to the originating point. No practical means have heretofore been devised for the compacting and storage of the empty tanks so as to free the interior of the basic shipping container or trailer for other purposes. In fact, prior to the present invention, any handling of the bag, whether positioning or removing the bag, or effecting a complete emptying thereof, required extensive manual labor.
The following patents, in addition to the above referred to Headrick patent, constitute the most pertinent prior art known to Applicant:
U.S. Pat. No. 2,712,797, Woehrle, et al., July 12, 1955
U.S. Pat. No. 2,803,491, Brown, Aug. 20, 1957
U.S. Pat. No. 3,514,151, Hacker, May 26, 1970
U.S. Pat. No. 3,756,469, Clark, et al., Sept. 4, 1973
U.S. Pat. No. 3,951,284, Fell, et al., Apr. 20, 1976
U.S. Pat. No. 3,980,196, Paulyson, et al., Sept. 14, 1976
U.S. Pat. No. 4,054,226, Bjelland, et al., Oct. 18, 1977